Ambient condition sensor for a photosensitive media cartridge

ABSTRACT

A photosensitive media cartridge includes an ambient condition sensor mounted in the cartridge for sensing ambient conditions in the cartridge. When the cartridge is positioned at a media transfer position on an image-forming device that permits the conveyance of media from the cartridge to the image-forming device, image development or printing on the media in the image-forming device is controlled based on the sensed ambient conditions in the cartridge. The ambient condition sensor includes a cover layer and a conductive layer, wherein a rate of response to ambient conditions of the cover layer matches rate of response to ambient conditions of the photosensitive media to be developed. As a further option, the media itself can include a conductive layer so that the media can be the sensor.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] Reference is made to commonly assigned copending applicationsSer. No. 09/597,924 filed Jun. 19, 2000, entitled AN IMAGE FORMINGDEVICE AND A METHOD OF PROCESSING PHOTOSENSITIVE MEDIA HAVINGMICROENCAPSULATED IMAGING MATERIAL, in the names of Loretta E. Allen,Yongcai Wang, Stephen M. Reinke and Yeh-Hung Lai; and Ser. No.09/597,928 filed Jun. 19, 2000, entitled AN IMAGING ASSEMBLY AND MEDIACARTRIDGE HAVING COOPERATING LINKAGE ARRANGEMENTS, in the names ofLoretta E. Allen, Yongcai Wang, Stephen M. Reinke and Yeh-Hung Lai; Ser.No. 09/597,999 filed Jun. 19, 2000 entitled A PHOTOSENSITIVE MEDIACARTRIDGE HAVING AN AMBIENT CONDITION SENSOR, filed in the names ofLoretta E. Allen, Yongcai Wang, Stephen M. Reinke and Lai Yeh-Hung.

FIELD OF THE INVENTION

[0002] The present invention relates to a sensor for sensing ambientconditions within a photosensitive media cartridge or at least in anenvironment surrounding the media or material in the cartridge. Thepresent invention further relates to an imaging arrangement in whichimaging of photosensitive material within an imaging device iscontrolled based on the sensed ambient conditions.

BACKGROUND OF THE INVENTION

[0003] Sensing apparatuses for sensing ambient conditions such ashumidity sensors are known. There are many mechanisms by which ahumidity sensor senses humidity. A few examples are conductivity,capacitance, and resistivity. Humidity sensors which utilize thesemechanisms are disclosed in U.S. Pat. Nos. 4,473,813, 4,298,855,4,635,027, and 5,348,761. These commercially available humidity sensorsare typically designed to have a quick response time to changes inhumidity.

[0004] Image-forming devices which process a photosensitive media ormaterial that includes microencapsulated coloring material are known. Inthese imaging devices the microcapsules are exposed to a radiation basedon image information. The microcapsules, whose mechanical strength canchange when exposed to light, are ruptured by means of a crushingpressure, whereupon the coloring material and other substancesencapsulated in the microcapsules are released and development occurs.For example, some systems use a pair of upper and lower nip rollers toapply pressure. In these systems, the photosensitive media is passedbetween the pair of upper and lower nip rollers which apply pressure torupture the microcapsules and begin development. Imaging devices thatemploy microencapsulted photosensitive compositions are disclosed inU.S. Pat. Nos. 4,399,209, 4,416,966, 4,440,846, 4,766,050, 5,783,353,and 5,916,727.

[0005] A problem in processing photosensitive media or material havingmicroencapsulated color-forming material is that printing and/or imagingcan be adversely affected by ambient conditions. That is, ambientconditions around the photosensitive media, or in the cartridge whichcarries the photosensitive media, can adversely affect subsequentprinting or development of the image. More specifically, ambientconditions such as humidity around the photosensitive media or in thecartridge which houses the photosensitive media, can have adverseaffects on the chemicals of the coloring material, the encapsulatingmaterial, and/or the photosensitive media. Further, the degree ofhardening or curing of the microcapsules and the concomitant increase inviscosity of the microcapsule varies with a change in humidity. As aresult, photographic characteristics such as speed, minimum and maximumdensity, fogging density and full color imaging can be adverselyaffected.

[0006] As discussed above, commercially available humidity sensors aretypically designed to have a quick response time to changes in humidity.On the other hand, photosensitive media or material tends to exhibit aslow rate of response to a change in conditions. That is, photosensitivemedia tends to have a slow equilibrium rate. Thus, commerciallyavailable humidity sensors do not respond at the same rate as thephotosensitive media or material with the result being that thesesensors do not provide a true representation of the level of relativehumidity on or around the media. Therefore, if a commercially availablehumidity sensor having a quick response to changes in humidity wereassociated with photosensitive media having a slow rate of change tohumidity, printing parameters for the photosensitive media would not becontrolled to optimum conditions. More specifically, if a commerciallyavailable humidity sensor was used to sense humidity values in acartridge carrying photosensitive material, when the cartridge is placedin an image-forming device, the humidity sensor would respond morerapidly to humidity conditions than the photosensitive material would.Therefore, the humidity value sensed by the humidity sensor would not berepresentative of the humidity value around the media. The control ofprinting parameters would thus be based on a humidity value which is notreflective of the level of humidity on or around the media.

SUMMARY OF THE INVENTION

[0007] The present invention provides for an ambient condition sensor,such as a humidity sensor, with a response time that is equal to ormatches the response time of the photosensitive media or material; amethod for manufacturing the ambient condition sensor; an image-formingdevice which utilizes the ambient condition sensor; and a method forprocessing photosensitive media which overcome the above-mentioneddrawbacks.

[0008] More specifically, the present invention relates to an imagingdevice in which photosensitive media that contains photosensitive,rupturable microcapsules can be first exposed and then developed byapplying pressure to the photosensitive media. In the image-formingdevice of the present invention, print image quality can be improved bysensing ambient conditions such as humidity in the image-forming device,directly from the media, or in the cartridge which carries the media,and adjusting at least one adjustable parameter based on the sensedambient condition. As an example, in response to a sensed humiditycondition, a controller or development member of the present inventioncan accordingly adjust the amount of pressure applied to themicrocapsules.

[0009] As indicated above, in the imaging device of the presentinvention, the photosensitive media contains photosensitive, rupturablemicrocapsules that are exposed and then developed by the application ofpressure using a stylus or pinch rollers to rupture unexposedmicrocapsules. Thereafter, the developed print may be fixed with heatsupplied by a heater in the imaging device. In the invention, the levelof relative humidity can be sensed inside and/or outside of theimage-forming device, in the media cartridge or directly on thephotosensitive media, and then at least one of the parameters of lightexposure, developing pressure, printing speed or fixing temperature canbe adjusted automatically on the basis of the relative humidity level toprovide an improved image. As an example, by adjusting the printingspeed for a printer, the so-called “dark time” which is the time betweenexposure and development will be changed. The dark time affects thehardness of microcapsules and therefore their crushability. Also, withinthe context of the present invention, the concept of sensing the levelof relative humidity on the photosensitive media refers to sensing themoisture content on or around the photosensitive media or material.

[0010] The present invention accordingly relates to an ambient conditionsensor for sensing ambient conditions in a cartridge which holdsphotosensitive material. The ambient condition sensor comprises a toplayer, a humidity responsive layer, a conductive layer and a basesupport layer. In the invention, a rate of response to ambientconditions of at least one of the top layer, the humidity responsivelayer, and the base support layer matches a rate of response to ambientconditions of photosensitive material in the cartridge.

[0011] The present invention further relates to a photosensitivematerial which comprises a transparent support layer, an imagingcomposition layer, a conductive layer and a base layer. Thephotosensitive material is positioned in a cartridge which holdsphotosensitive material to be developed and is adapted to sense ambientconditions around the photosensitive material in the cartridge.

[0012] The present invention further relates to a photosensitive mediacartridge which comprises a housing adapted to hold a stack ofphotosensitive media; and an ambient condition sensor positioned withinthe housing for sensing ambient conditions around photosensitive mediain the housing and providing an ambient condition signal indicativethereof. A development of the photosensitive media is based on thesensed ambient conditions. The ambient condition sensor comprises atransparent top layer, a humidity responsive layer, a conductive layerand a base support layer. A rate of response to ambient conditions of atleast one of the transparent top layer, the humidity responsive layer,and the base support layer matches a rate of response to ambientconditions of the photosensitive media in the housing.

[0013] The present invention further relates to a photosensitive mediacartridge which comprises a housing adapted to hold a stack ofphotosensitive media, such that at least one of the photosensitive mediain the stack of photosensitive media comprises a transparent supportlayer, an imaging composition layer, a conductive layer and a baselayer. At least one photosensitive media having the conductive layer isadapted to sense ambient conditions around the photosensitive media insaid housing.

[0014] The present invention further relates to an image-formingarrangement which comprises an image-forming device for forming a latentimage on a photosensitive media; and a media cartridge for holding astack of photosensitive media therein. The media cartridge is adapted tobe inserted into the image-forming device to permit a conveyance of thephotosensitive media to the image-forming device. The media cartridgecomprises an ambient condition sensor for sensing ambient conditionsaround media in the cartridge, such that a development of thephotosensitive media in the image-forming device is based on the sensedambient conditions. The ambient condition sensor comprises a transparenttop layer, a humidity responsive layer, a conductive layer and a basesupport layer, wherein a rate of response to ambient conditions of atleast one of the transparent top layer, the humidity responsive layer,and the base support layer matches a rate of response to ambientconditions of the photosensitive media in the media cartridge.

[0015] The present invention further relates to an image-formingarrangement which comprises an image-forming device for forming a latentimage on a photosensitive media; and a media cartridge adapted to hold astack of photosensitive media, wherein at least one of thephotosensitive media in the stack of photosensitive media comprises atransparent support layer, an imaging composition layer, a conductivelayer and a base layer. The at least one photosensitive media having theconductive layer is adapted to sense ambient conditions around thephotosensitive media in the housing and a development of thephotosensitive media in the image-forming device is based on the sensedambient conditions.

[0016] The present invention further relates to a photosensitive mediacartridge which comprises a housing adapted to hold a stack ofphotosensitive media, such that all of the media in the stack ofphotosensitive media comprises a transparent support layer, an imagingcomposition layer, a conductive layer and a base layer. Thephotosensitive media having the conductive layer is adapted to senseambient conditions around the photosensitive media in said housing.

[0017] The present invention further relates to an image-formingarrangement which comprises an image-forming device for forming a latentimage on a photosensitive media; and a media cartridge adapted to hold astack of photosensitive media, wherein all of the media in the stack ofphotosensitive media comprises a transparent support layer, an imagingcomposition layer, a conductive layer and a base layer. Thephotosensitive media having the conductive layer is adapted to senseambient conditions around the photosensitive media in the housing and adevelopment of the photosensitive media in the image-forming device isbased on the sensed ambient conditions.

[0018] The present invention further relates to a method of producing anambient condition sensor for photosensitive material to be developed.The method comprises providing at least one cover layer on a conductivelayer; and placing the conductive layer having at least one cover layerthereon in a cartridge which is adapted to hold photosensitive materialto be developed therein, such that a rate of response to ambientconditions of at least the cover layer matches a rate of response toambient conditions of the photosensitive material in the cartridge.

[0019] The present invention further relates to a method of controllingimage development which comprises providing an ambient condition sensorin a cartridge which holds photosensitive media therein, with theambient condition sensor sensing ambient conditions aroundphotosensitive media in the cartridge, the ambient condition sensorcomprising at least a cover layer and a conductive layer, and a rate ofresponse to ambient conditions of at least the cover layer matches arate of response to ambient conditions of the photosensitive media inthe media cartridge; inserting the cartridge to an insertion position inan imaging device which permits a passage of photosensitive media fromthe cartridge to the imaging device; sensing ambient conditions aroundthe photosensitive media by way of the ambient condition sensor; andcontrolling a development of images on the photosensitive media based onthe sensed ambient conditions.

[0020] The present invention further relates to an ambient conditionsensor for a photosensitive material imaging arrangement which comprisesa cover layer and a conductive layer, wherein a rate of response toambient conditions of the cover layer matches a rate of response toambient conditions of a photosensitive material to be developed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 schematically illustrates one example of an image-formingarrangement in accordance with the present invention;

[0022]FIG. 2 schematically illustrates a microprocessor for controllingthe operation of the image-forming arrangement of FIG. 1;

[0023]FIG. 3(a) illustrates a first embodiment of a pressure applyingassembly of the image-forming arrangement of the present invention;

[0024]FIG. 3(b) is a side view of the pressure applying assembly of FIG.3(a).

[0025]FIG. 3(c) is a further view of the pressure applying assembly ofFIG. 3(a);

[0026]FIG. 4(a) shows a device for sensing ambient conditions in aphotosensitive media cartridge in accordance with one feature of theinvention;

[0027]FIG. 4(b) shows a device for sensing ambient conditions in animage forming device in accordance with the present invention;

[0028]FIG. 4(c) shows another device for sensing ambient conditions in aphotosensitive media cartridge in accordance with a further feature ofthe invention;

[0029]FIG. 5(a) shows an ambient condition sensor in accordance with thepresent invention;

[0030]FIG. 5(b) is a cross sectional view of FIG. 5(a) taken along linea-a;

[0031]FIG. 6(a) shows another ambient condition sensor in accordancewith the present invention;

[0032]FIG. 6(b) is a cross sectional view of FIG. 6(a) taken along linea-a;

[0033]FIG. 6(c) shows another device for sensing ambient conditions in aphotosensitive media cartridge in accordance with a further feature ofthe present invention;

[0034]FIG. 6(d) shows another device for sensing ambient conditions in aphotosensitive media cartridge in accordance with a further feature ofthe present invention;

[0035]FIG. 7(a) shows yet another ambient condition sensor in accordancewith the present invention;

[0036]FIG. 7(b) is a cross sectional view of FIG. 7(a) taken along linea-a; and

[0037]FIG. 7(c) schematically illustrates another example of animage-forming arrangement in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0038] Referring now to the drawings, wherein like reference numeralsrepresent identical or corresponding parts throughout the several views,FIG. 1 is a schematic view of an image-forming device 15 of the presentinvention. Image-forming device 15 could be, for example, a printer thatincludes an opening 17 which is adapted to receive a cartridge 85containing photosensitive media 47. As described in U.S. Pat. No.5,884,114, the cartridge could be a light-tight cartridge in whichphotosensitive sheets, media or material are piled one on top of eachother. When inserted into image-forming device 15, a feed mechanismwhich includes, for example, a feed roller 21 a in image-forming device15, working in combination with a mechanism in the cartridge, cooperatewith each other to pull one sheet at a time from the cartridge intoimage-forming device 15 in a known manner. Once inside image-formingdevice 15, photosensitive media 47 travels along media path 19, and istransported by, for example, drive rollers 21 connected to, for example,a driving mechanism such as a motor. The photosensitive media will passby an imaging head 25 which could include a plurality of light emittingelements that are effective to expose a latent image on thephotosensitive media based on image information. After the latent imageis formed, the photosensitive media is conveyed past a developmentmember such as a pressure applicator or pressure assembly 27, where animage such as a color image is formed based on the image information byapplying pressure to microcapsules having imaging material encapsulatedtherein to crush the microcapsules. Within the context of the presentinvention, the imaging material comprises a coloring material (which isused to form images) or material for black and white media. After theformation of the image, the photosensitive media is conveyed past aheater 29 for fixing the image on the media. In a through-feed unit, thephotosensitive media could thereafter be withdrawn through an exit 32.As a further option, image-forming device 15 can be a return unit inwhich the photosensitive media is conveyed or returned back to opening17.

[0039] In a feature of the present invention, image-forming device 15includes a microprocessor or controller 30, illustrated in detail inFIG. 2. Controller 30 controls several printing parameters with respectto the development of the image on the photosensitive media. Forexample, controller 30 can control parameters such as light exposure,pressure application, fixing temperature, printer motor speed, etc.

[0040] With reference to FIG. 2, a first feature of image-forming device15 and controller 30 of the present invention is the control of printingconditions based on sensed ambient conditions. More specifically,controller 30 is adapted to be responsive to ambient conditions toprovide a pressure increasing or pressure decreasing signal to pressureassembly 27 to control the amount of pressure or crushing force appliedby pressure assembly 27.

[0041] In one example of the invention as illustrated in FIG. 2,controller 30 is operationally associated with an ambient conditionsensor which senses ambient conditions within image-forming device 15.As shown in FIG. 2, the ambient condition sensor can be a humiditysensor 33 which senses humidity conditions within image-forming device15. As will be explained in detail later, the invention is not limitedto sensing the humidity within image-forming device 15. It is noted thatthe humidity can be sensed outside of image-forming device 15. Withinthe context of the present invention, the humidity is sensed within aphotosensitive media cartridge and/or directly from or around thephotosensitive media itself.

[0042] Once the humidity is sensed by humidity sensor 33, a signalindicative thereof is sent to a look-up table 34. Look-up table 34 caninclude a plurality of reference humidity values which are compared tothe sensed humidity value. Within the context of the present invention,the term reference humidity value refers to a humidity level or morepreferably, a response curve (printing pressure vs. humidity). As afurther option, rather than using a look-up table, an equation or adirect circuit can be utilized. Once this comparison is made, controller30 can drive a drive circuit 35 for controlling the pressure applicationby pressure assembly 27. As an example, it is beneficial to apply alarger amount of pressure when a sensed humidity is high (for example,higher than a reference humidity value of 30%) and to reduce thepressure applied to the photosensitive material when the sensed humidityis low (for example, lower than a reference humidity value of 30%). Ofcourse, it is noted that the present invention is not limited to theabove-reference humidity value. It is noted that the reference humidityvalue can be any value which is set based on a desired result. As anexample, a reference humidity value which provides consistentsensitometric properties can be used.

[0043] As a further example, it is beneficial to reduce the pressureapplied to the photosensitive material, or increase the level of lightexposure, or to reduce the printing speed when the sensed humidity islow. These changes can be done according to precalibrated informationstored in the printer or stored on the cartridge through a barcode.Under certain conditions, it is desirable to change several parameterssimultaneously according to the humidity information to optimize theprinting conditions.

[0044] The precalibrated information for a given type of media can beobtained by testing the sensitometric characteristics of the media as afunction of, for example, printing pressure or light exposure level. Thedetails of response of printing pressure to humidity depend on themedia. But it is in general theorized that the mechanical properties ofa microcapsule containing layer changes with humidity which in turnchanges the response of the microcapsule containing layer to printingpressure. For example, if the microcapsule containing layer is rigid atlower humidity (e.g. 30% RH) the microcapsules are more easily ruptured.If the microcapsule layer becomes more flexible at high humidity (e.g.80%RH) the microcapsules are more difficult to rupture. This may changethe amount of coloring materials released by the microcapsules duringthe printing process. Thus, the reference humidity depends on the typeof media and level of light exposure.

[0045] Therefore, if the sensed humidity is higher than the referencehumidity value, the drive circuit will provide a signal to pressureassembly 27 to increase the amount of pressure applied to thephotosensitive media, and if the humidity value is lower, the drivecircuit will provide a signal to pressure assembly 27 to reduce theamount of pressure applied to the photosensitive media.

[0046] As also indicated above, controller 30 is adapted to controlfeatures of imaging head 25, heater 29, as well as a motor 37 fordriving rollers 21 and conveying media 47 through image-forming device15 to control printing speed. As a further option, these features couldalso be controlled based on the sensed humidity value. Further featuresof image-forming device 15 and controller 30 include the provision of acontrol panel 41 to enable user control of image-forming device 15, animage card 39 which can include image information with respect to theimage which is to be developed and printed, and a display 80 (FIG. 1)for displaying information, such as image information or the sensedhumidity value.

[0047] As a further option, images which are to be printed byimage-forming device 15 can be transferred or uploaded to image-formingdevice 15 by way of the Internet or a computer. For example, as shown inFIG. 2, image-forming device 15 or controller 30 can include a modem 800for communication to a network service provider 801 such as theInternet. This permits a transfer of images to image-forming device 15from the Internet for subsequent printing. As a further example,image-forming device 15 or controller 30 can include a PC interface 803in communication with a computer 805 such as a personal computer. Thispermits the transfer of images stored in computer 805 to image-formingdevice 15 for subsequent printing. As a further option, computer 805 canbe communicated to Network service provider 801 to download images fromthe Internet to image-forming device 15 via computer 805.

[0048] FIGS. 3(a), 3(b) and 3(c) illustrate different views of anembodiment of pressure assembly 27 in accordance with the presentinvention. Pressure assembly 27 can comprise a crushing roller and beamarrangement which provides a point contact on photosensitive media 47.More specifically, pressure assembly 27 includes a slide 45 whichextends along a width-wise direction of a photosensitive media 47.Moveably mounted on slide 45 is a crushing roller arrangement 49 whichis adapted to move along the length of slide 45, i.e., across the widthof photosensitive media 47. Crushing roller arrangement 49 is adapted tocontact one side of photosensitive media 47. A beam 51 is positioned soas to contact the opposite side of photosensitive media 47 and islocated opposite crushing roller 49. Beam 51 and crushing rollerarrangement 49 when in contact with photosensitive media 47 on oppositesides provide a point contact on photosensitive media 47. Crushingroller arrangement 49 is adapted to move along a width-wise direction ofphotosensitive material 47 so as to crush microcapsules, releasecoloring material, and process image information such as imageinformation provided by image card 39.

[0049] Extending from beam 51 is an arm 53 having an extension or seatportion 55. Also provided on beam 51 are compression springs 57 whichurge beam 51 into contact with a lower side of photosensitive media 47.It is further noted that beam 51 and arm 53 are pivotally mounted at apivot point 59 so as to be movable or rotatable about pivot point 59 asillustrated by arrow 61. Thus, compression spring 57 urges beam 51 andarm 53 in a clockwise direction about pivot point 59, so as to urge beam51 into contact with the lower surface of media 47. In a further featureof pressure assembly 27 as illustrated in FIGS. 3(a)-3(c), anelectromagnet 60 is positioned adjacent to extension 55.

[0050] Thus, compression spring 57 urges beam 51 in a clockwisedirection so as to place beam 51 in a pressure applying position.Electromagnet 60 mounted to a printer frame (not shown) applies aninitial attraction force to extension 55 and arm 53 so as to helpmaintain beam 51 in the pressure applying position. As illustrated inFIG. 2, pressure assembly 27 receives a signal from controller 30. Inthe embodiment of FIGS. 3(a)-3(c), electromagnet 60 is operationallyconnected to controller 30 via drive circuit 35.

[0051] An operation of pressure assembly 27 will now be described. Withreference to FIGS. 1, 2 and 3(a)-3(c), in one embodiment of theinvention, humidity within the housing of image-forming device 15 issensed by humidity sensor 33. This provides a signal to look-up table 34within controller 30. If the sensed humidity is above a humidityreference value or response curve, a pressure-increasing signal will beapplied to drive circuit 35 so as to increase the pressure applied bypressure assembly 27. More specifically, in response to a pressureincreasing signal, controller 30 will interact with electromagnet 60 toincrease the attraction force on extension 55 and in turn on arm 53, andtherefore increase the initial attraction force to further pivot arm 53and beam 51 in the clockwise direction towards photosensitive media 47.This increases the pressure applied by beam 51 on photosensitive media47, and increases the crushing force applied to the microcapsules viabeam 51 and crushing roller 49. If the humidity sensed by humiditysensor 33 is below a reference humidity value, controller 30 willprovide a signal to drive circuit 35 to decrease the pressure applied bypressure assembly 27. In this scenario, controller 30 will interact withelectromagnet 60 to reduce the attraction force back to the initialattraction force.

[0052] Thus, when electromagnet 60 receives a signal from controller 30indicating that the sensed humidity is lower than a reference humidity,a pressure decreasing signal is provided by controller 30 toelectromagnet 60. The signal causes electromagnet 60 to reduce theattraction force against arm 53 back to the initial attraction force,and thus return beam 51 and arm 53 to its initial pressure applyingposition.

[0053] It is noted that the structure of the pressure assembly 27 is notlimited to the embodiment shown in FIGS. 3(a)-3(c). As examples, thepressure assembly can take to form of a full length clamping springresponsive to a magnetic force; or a pulley and extension springarrangement which is actuated by a motor (see, for example, copendingapplication Ser. No. 09/597,924).

[0054] The invention has thus for been described with respect to 30measuring ambient conditions such as humidity within the housing ofimage-forming device 15. As previously indicated, the invention is notlimited to such an arrangement. For example, the humidity within acartridge which holds photosensitive media that is to be fed intoimage-forming device 15 can be sensed. FIGS. 4(a) and 4(c) illustrateembodiments for sensing humidity within a cartridge.

[0055] More specifically, FIG. 4(a) is an exploded view of a cartridge85 that holds photosensitive media 47′. Media 47′ could be of the typehaving microcapsules with coloring material. As shown in FIG. 4(a),media cartridge 85 defines a housing having top and bottom sections 85a, 85 b which can snap together to house media 47′ therein, one on topof the other. Cartridge 85 further includes a light-lock door 85 c and aspring plate 89. Cartridge 85 and more specifically, one of the sections85 a, 85 b of cartridge 85 includes a humidity sensor 87 which comprisesa first contact plate 90 having a first electrode 91 and a secondcontact plate 95 having a second electrode 97. Sandwiched between firstand second contact plates 90 and 95 is a sampling member or dielectriclayer 93. Sampling member 93 could be a material which is susceptible orresponsive to humidity conditions within cartridge 85. An example ofthis could be a salt solution impregnated fabric or various hydrophilicpolymers.

[0056] Therefore, in the arrangement of FIG. 4(a), electrodes 97 and 91provide for a capacitor and the measured humidity is a function ofcapacitance. Electrodes 97 and 91 protrude through cutouts 99 in springplate 89 and corresponding cutouts in section 85 b to make physicalcontact between sensor 87 located within cartridge 85 and controller 30located within image-forming device 15. Based on the signal fromhumidity sensor 87, controller 30 controls the application of pressureby way of pressure assembly 27 in the manner described with respect toFIGS. 3(a)-3(c). Humidity sensor 87 as illustrated in FIG. 4(a) canreplace humidity sensor 33 in the housing of image-forming device 15 orbe used in addition to sensor 33. As previously described, a higherhumidity would provide a signal to increase the pressure applied bypressure assembly 27, while a lower humidity would provide a signal tocontroller 30 to control the pressure assembly to lower the crushingpressure. Thus, an image-forming arrangement or assembly would becomprised of at least the cartridge and the image-forming device.

[0057]FIG. 4(b) illustrates another method for measuring humidity as afunction of capacitance could be done within the housing ofimage-forming device 15. In this example, electrodes 91 and 97 aremounted at a predetermined distance apart from each other and arelocated in the media path. As media 47′ travels through image-formingdevice 15 along the media path, it momentarily pauses when a sufficientarea of media is located between the contact plates. Media 47′ would nowbe used as the sampling member, and a measurement for capacitance ismade.

[0058]FIG. 4(c) illustrates another embodiment for sensing humiditywithin a cartridge. More specifically, FIG. 4(c) is an exploded view ofa cartridge 85′ that holds photosensitive media 47′. Media 47′ could beof the type having microcapsules with coloring material. As shown inFIG. 4(c), media cartridge 85′ define a housing having top and bottomsections 85 a′, 85 b′ which can snap together to house media 47′therein, one on top of the other. Cartridge 85′ further includes a lightlock door 85 c′ and a spring plate 89′. Cartridge 85′ and morespecifically, one of the sections 85 a′, 85 b′ of cartridge 85′ includesa humidity sensor 87′ which comprises a substrate 400 withinterdigitated conductive terminals on the substrate overcoated with ahumidity responsive material such as a hydrophilic polymer. An exampleof this device comprises an ESTAR™ substrate onto which a 1000-2000 Åthick layer of nickel is deposited. The interdigitated terminal patterncan be formed by laser ablation. The humidity responsive material can bea layer comprising gelatin and an antistat agent such as a quarternaryamine compound. The humidity responsive material is evenly coated ontoto the conductive terminals leaving a portion of the terminals exposedfor electrical contacts. Humidity effects the electrical properties ofthe polymer and the relative humidity can be obtained directly from theequivalent resistance or conductance of the sensor. Electrodes 91′and97′ protrude through cut-outs in bottom section 85 b′ of cartridge 85′to make physical contact between sensor 87′ located within cartridge 85′and controller 30 located within image-forming device 15.

[0059] Referring now to FIGS. 5(a) and 5(b), an embodiment of a humiditysensor 500 in accordance with the present invention is shown. Morespecifically, sensor 500 in accordance with the present invention isdesigned to have a response time that is equal to or matches theresponse time of photosensitive media. Sensor 500 basically includes ahumidity sensitive member such as a humidity responsive layer 501. As anexample, humidity responsive layer 501 is preferably a materialcomprising approximately 762 mg/m² gelatin and approximately 76.2 mg/m²of a quarternary amine compound called Cyastat SP Antistatic. Of course,the example given above is a non-limiting example, and it is recognizedthat other types of humidity responsive materials can be utilized. It isfurther recognized that the above noted proportion of the materials canbe varied based on design considerations. Humidity effects theelectrical properties of humidity responsive layer 501 and the relativehumidity can be obtained directly from the equivalent resistance orconductance of the sensor. Humidity sensor 500 further includes a topsupport 503 and a base support 505. Sandwiched between base support 505and humidity responsive layer 501 is a conductive layer 507 whichincludes interdigited fingers having first and second electricalcontacts 509 a, 509 b. A feature of sensor 500 is that a layer, forexample, at least one of humidity responsive layer 501, top support 503or base support 505 is made of a material having properties which aresimilar or match the properties of photosensitive material 47′ in mediacartridge 85 or 85′. More specifically, at least one of humidityresponsive layer 501, top support 503 and base support 505 has a rate ofresponse to ambient conditions, such as relative humidity, in and aroundthe photosensitive media, which matches the rate of response to ambientconditions of the photosensitive material. For example at least one ofhumidity responsive layer 501, top support 503 and base support 505 is abarrier to the diffusion of water at a rate that matches the rate ofwater diffusion of media in the cartridge. With this arrangement, sensor500 would essentially be pre-calibrated to the photosensitive media inthe cartridge. Therefore, when the cartridge is inserted intoimage-forming device 15, the ambient conditions as sensed by ambientcondition sensor 500 would essentially be reflective of the ambientconditions of the photosensitive material. For example, if thephotosensitive material has a slow rate of response when a cartridge isinserted into the image-forming device, the rate of response of sensor500 would match the rate of response of the photosensitive material soas to provide for a true measure of the level of humidity on thephotosensitive media. This signal is provided to controller 30 asdescribed with respect to, for example FIGS. 4(a), 4(c), via contacts509 a, 509 b. More specifically, contacts 509 a, 509 b protrude throughcutouts in cartridge 85 or 85′ to make physical contact between sensor500 located within the cartridge and controller 30 located withinimage-forming device 15 to control development of the photosensitivematerial. Thus, an image-forming arrangement would be comprised of atleast a cartridge which holds sensor 500 and image-forming device 15.

[0060] As illustrated in FIG. 5(b), in a preferred embodiment of ambientcondition sensor 500, top support 503 and humidity responsive layer 501have a length which does not extend over electrical contacts 509 a, 509b. On the other hand, the length of base support 505 matches the lengthof conductive layer 507 including electrical contacts 509 a, 509 b. Thispermits a portion of electrical contacts 509 a, 509 b to be exposed onone side.

[0061] It is noted that the use of ambient condition sensor 500 asillustrated in FIGS. 5(a), 5(b) is not limited to the imagingarrangements described in the present specification. More specifically,ambient condition sensor 500 as illustrated in FIGS. 5(a), 5(b) can beutilized in any type of imaging arrangement in which development ofphotosensitive media in the imaging arrangement is based on ambientconditions such as humidity on the photosensitive media located in acartridge.

[0062] FIGS. 6(a), 6(b) and 6(c) illustrate a further embodiment of anambient condition sensor in accordance with the present invention. Inthe embodiment of FIGS. 6(a), 6(b), 6(c), the ambient condition sensortakes the form of the photosensitive media or material itself. Thus, theambient condition sensor would comprise the same structure as thephotosensitive media and also would be essentially pre-calibrated. FIGS.6(a) and 6(b) illustrates such a photosensitive media 600 sensor whichacts as an ambient condition sensor. As shown in FIGS. 6(a) and 6(b),media 600 includes a first transparent support 601; a subbing layer 603;an image composition layer 605 which includes photo-hardenablemicrocapsules 607 and a developer material 609; a layer of adhesive 615;and a second support layer 614. Second support layer 614 may or may notcontain an opacifying agent 617. For features of the photosensitivemedia reference is made to U.S. Pat. No. 5,783,353. The imagecomposition layer 605 should be ionic in nature in order to be humidityresponsive. To enhance the response of the image composition layer 605,an anti-static agent can be added during manufacturing. An example of ananti-static agent is a 50% solution of quaternary ammonium compound inisopropanol.

[0063] In a feature of the present invention as illustrated in FIGS.6(a), 6(b), photosensitive media 600 further includes a layer 611 whichis a conductive layer. In a preferred embodiment, conductive layer 611is transparent, for example indium tin oxide (ITO), or matches the colorof an opaque second support layer 614, and includes interdigited fingershaving first and second electrical contacts 611 a, 611 b. As illustratedin FIG. 6(b), in a preferred embodiment of ambient condition sensor 600,second support layer 614 and adhesive layer 615 have a length which doesnot extend over the entire surface of electrical contacts 611 a, 611 b.On the other hand, the length of first transparent support 601 andsubbing layer 603 matches the length of conductive layer 611 includingelectrical contacts 611 a, 611 b. This permits a portion of electricalcontacts 611 a, 611 b to be exposed on one side. In this embodiment,humidity effects the electrical properties of the image compositionlayer 605 and the relative humidity can be obtained directly from theequivalent resistance or conductance of the sensor.

[0064] With the embodiment of FIGS. 6(a), 6(b), photosensitive media 600can be positioned in a cartridge 85″ as illustrated in FIG. 6(c).Cartridge 85″ includes top and bottom sections 85 a″ and 85 b″. In onefeature of the invention, only one photosensitive media of a stack ofphotosensitive media 70 in cartridge 85″ would have the structureillustrated in FIG. 6(a) and would act as an ambient condition sensor.Photosensitive media 600 acting as an ambient condition sensor would belocated at the bottom of the stack of photosensitive media 70, and wouldremain in cartridge 85″ until all the other pieces of photosensitivemedia have been removed. Photosensitive media 600 acting as the ambientcondition sensor would be calibrated to the media and would provide atrue reflection of the ambient condition; such as humidity value,surrounding the media when the cartridge is inserted into an imagingdevice or apparatus. More specifically, electrical contacts 611 a, 611 bas shown in FIG. 6(b) would cooperate with conductive contact portions893, 894 on spring plate 89″ to provide an electrical signal tocontroller 30 located within the image-forming device to controldevelopment as previously described. Thus, an image-forming arrangementwould be comprised of at least a cartridge which holds photosensitivemedia 600 that acts as an ambient condition sensor and image-formingdevice 15.

[0065] As a further option, all of the media in the stack ofphotosensitive media could include a conductive layer, and thus eachindividual media would act as a separate ambient condition sensor asshown in FIG. 6(d).

[0066] FIGS. 7(a)-7(c) illustrates a further embodiment of an ambientcondition sensor in accordance with the present invention. In theembodiment of FIGS. 7(a)-7(c), an ambient condition sensor takes theform of photosensitive media or material itself. Thus, the ambientcondition sensor would comprise the same structure as the media and alsowould be essentially pre-calibrated. FIGS. 7(a) and 7(b) illustrate sucha photosensitive media or ambient condition sensor 700. Ambientcondition sensor 700 includes a first transparent support 701; a subbinglayer 703; an image composition layer 705 which includesphoto-hardenable microcapsules 707 and a developer material 709; a layerof adhesive 715; and a second support layer 714. Second support layer714 may or may not contain an opacifying agent 717. For features of thephotosensitive media reference is made U.S. Pat. No. 5,783,353.

[0067] In a feature of the present invention as illustrated in FIGS.7(a) and 7(b), sensor 700 further includes layer 711 which is aconductive layer. In a preferred embodiment, conductive layer 711 istransparent or matches the color of an opaque second support layer 714.In the embodiment of FIGS. 7(a) and 7(b), conductive layer 711 includeselectrical contacts 711 a, 711 b. As illustrated in FIG. 7(b), in apreferred embodiment of ambient condition sensor 700, first transparentsupport 701, subbing layer 703, and image composition layer 705 have alength which does not extend over the entire surface of electricalcontacts 711 a, 711 b. On the other hand, the length of adhesive layer715 and second support layer 714 matches the length of conductive layer711 including electrical contacts 711 a, 711 b. This permits a portionof electrical contacts 711 a, 711 b to be exposed on one side whichwould be opposite to the exposed side of the electrical contacts in theembodiment of FIG. 6(b). In the embodiment of FIGS. 7(a)-7(b), humidityeffects the electrical properties of the image composition layer 705 andthe relative humidity can be obtained directly from the equivalentresistance or conductance of the ambient condition sensor.

[0068] With the arrangement of FIGS. 7(a), 7(b) with respect to theexposed side of contacts 711 a, 711 b, contact can be made as shown inFIG. 7(c). More specifically, as photosensitive media 700 which acts asan ambient condition sensor is withdrawn from cartridge 85 and is driventhrough the printing process along media path 19, conductive fingers 719connected to controller 30 are positioned such that they make contactwith electrical contacts 711 a, 711 b and transfer an electrical signalto controller 30. Like the embodiment noted above, it is recognized thatphotosensitive media 700 which acts as an ambient condition sensor isnot limited for use in imaging apparatuses as illustrated in the presentdescription. More specifically, the photosensitive media 700 which actsas an ambient condition sensor can be utilized in any imagingarrangement where it is desirable to control development based onambient conditions surrounding media in a cartridge.

[0069] The invention has been described in detail with particularreference to certain preferred embodiments thereof but it will beunderstood that variations and modifications can be effected within thespirit and scope of the invention.

What is claimed is:
 1. An ambient condition sensor for sensing ambientconditions in a cartridge which holds photosensitive material, theambient condition sensor comprising: a top layer, a humidity responsivelayer, a conductive layer and a base support layer, wherein a rate ofresponse to ambient conditions of at least one of said top layer, saidhumidity responsive layer, and said base support layer matches a rate ofresponse to ambient conditions of photosensitive material in thecartridge.
 2. A sensor according to claim 1, wherein said conductivelayer comprises conductive interdigited fingers and first and secondelectrical contacts.
 3. A sensor according to claim 1, wherein saidambient conditions is reflective of humidity conditions around thephotosensitive material in the cartridge.
 4. A sensor according to claim1, wherein a development of the photosensitive material is based on thesensed ambient conditions by said sensor.
 5. A sensor according to claim1, wherein said photosensitive material to be developed comprisesmicrocapsules which encapsulate imaging material.
 6. A sensor accordingto claim 5, wherein said imaging material comprises coloring material.7. A photosensitive material comprising: a transparent support layer, animaging composition layer, a conductive layer and a base layer, suchthat said photosensitive material is positioned in a cartridge whichholds photosensitive material to be developed and the photosensitivematerial is adapted to sense ambient conditions around thephotosensitive material.
 8. A photosensitive material according to claim7, wherein said conductive layer is transparent.
 9. A photosensitivematerial according to claim 7, wherein said base layer is an opaque basesupport layer and said conductive layer matches a color of said opaquebase support layer.
 10. A photosensitive material according to claim 7,wherein said conductive layer comprises conductive interdigited fingersand first and second electrical contacts.
 11. A photosensitive materialaccording to claim 7, wherein said image composition layer comprisesmicrocapsules which encapsulate imaging material.
 12. A photosensitivematerial according to claim 11, wherein said imaging material comprisescoloring material.
 13. A photosensitive media cartridge comprising: ahousing adapted to hold a stack of photosensitive media; and an ambientcondition sensor positioned within said housing for sensing ambientconditions around photosensitive media in said housing and providing anambient condition signal indicative thereof, such that a development ofthe photosensitive media is based on the sensed ambient conditions; saidambient condition sensor comprising a top layer, a humidity responsivelayer, a conductive layer and a base support layer, wherein a rate ofresponse to ambient conditions of at least one of said transparent toplayer, said humidity responsive layer, and said base support layermatches a rate of response to ambient conditions of the photosensitivemedia in said housing.
 14. A cartridge according to claim 13, whereinsaid conductive layer comprises conductive interdigited fingers andfirst and second electrical contacts.
 15. A cartridge according to claim13, wherein said ambient conditions is reflective of humidity conditionsaround the photosensitive media in said housing.
 16. A cartridgeaccording to claim 13, wherein said photosensitive media comprisesmicrocapsules which encapsulate imaging material.
 17. A cartridgeaccording to claim 17, wherein said imaging material comprises coloringmaterial.
 18. A photosensitive media cartridge comprising: a housingadapted to hold a stack of photosensitive media, wherein at least one ofthe photosensitive media in the stack of photosensitive media comprisesa transparent support layer, an imaging composition layer, a conductivelayer and a base layer, such that said at least one photosensitive mediahaving said conductive layer is adapted to sense ambient conditionsaround the photosensitive media in said housing.
 19. A photosensitivemedia cartridge according to claim 18, wherein said conductive layer istransparent.
 20. A photosensitive media cartridge according to claim 18,wherein said base layer is an opaque base support layer and saidconductive layer matches a color of said opaque base support layer. 21.A photosensitive media cartridge according to claim 18, wherein saidconductive layer comprises conductive interdigited fingers and first andsecond electrical contacts.
 22. A photosensitive media cartridgeaccording to claim 18, wherein said image composition layer comprisesmicrocapsules which encapsulate imaging material.
 23. A photosensitivemedia cartridge according to claim 22, wherein said imaging materialcomprises coloring material.
 24. An image-forming arrangementcomprising: an image-forming device for forming a latent image on aphotosensitive media; and a media cartridge for holding a stack ofphotosensitive media therein, said media cartridge being adapted to beinserted into said image-forming device to permit a conveyance of thephotosensitive media to the image-forming device, said media cartridgecomprising an ambient condition sensor for sensing ambient conditionsaround media in said cartridge, such that a development of thephotosensitive media in said image-forming device is based on the sensedambient conditions; said ambient condition sensor comprising atransparent top layer, a humidity responsive layer, a conductive layerand a base support layer, wherein a rate of response to ambientconditions of at least one of said transparent top layer, said humidityresponsive layer, and said base support layer matches a rate of responseto ambient conditions of the photosensitive media in the mediacartridge.
 25. An image-forming arrangement according to claim 24,wherein said conductive layer comprises conductive interdigited fingersand first and second electrical contacts.
 26. An image-formingarrangement according to claim 24, wherein said ambient conditions isreflective of humidity conditions around the photosensitive media in thecartridge.
 27. An image-forming arrangement according to claim 24,wherein said photosensitive media comprises microcapsules whichencapsulate imaging material.
 28. An image-forming arrangement accordingto claim 27, wherein said imaging material comprises coloring material.29. An image-forming arrangement comprising: an image-forming device forforming a latent image on a photosensitive media; and a media cartridgeadapted to hold a stack of photosensitive media, wherein at least one ofthe photosensitive media in the stack of photosensitive media comprisesa transparent support layer, an imaging composition layer, a conductivelayer and a base layer, such that said at least one photosensitive mediahaving said conductive layer is adapted to sense ambient conditionsaround the photosensitive media in said housing and a development of thephotosensitive media in said image-forming device is based on the sensedambient conditions.
 30. An image-forming arrangement according to claim29, wherein said conductive layer is transparent.
 31. An image-formingarrangement according to claim 29, wherein said base layer is an opaquebase support layer and said conductive layer matches a color of saidopaque base support layer.
 32. An image-forming arrangement according toclaim 29, wherein said conductive layer comprises conductiveinterdigited fingers and first and second electrical contacts.
 33. Animage-forming arrangement according to claim 29, wherein said imagecomposition layer comprises microcapsules which encapsulate imagingmaterial.
 34. An image-forming arrangement according to claim 29,wherein said imaging material comprises coloring material.
 35. Animage-forming arrangement according to claim 29, wherein said ambientconditions is reflective of humidity conditions around thephotosensitive media in the cartridge.
 36. A method of producing anambient condition sensor for photosensitive material to be developed,the method comprising: providing a cover layer on a conductive layer;and placing the conductive layer having the cover layer thereon in acartridge which is adapted to hold photosensitive material to bedeveloped therein, such that a rate of response to ambient conditions ofat least the cover layer matches a rate of response to ambientconditions of the photosensitive material in the cartridge.
 37. A methodaccording to claim 36, wherein said cover layer is a humidity responsivelayer and said conductive layer comprises conductive interdigitedfingers and first and second electrical contacts.
 38. A method ofproducing an ambient condition sensor according to claim 36, furthercomprising: adding an image composition layer to said conductive layerhaving said cover layer thereon, such that imaging properties of saidambient condition sensor matches imaging properties of thephotosensitive material to be developed.
 39. A method according to claim38, wherein said image composition layer comprises microcapsules whichencapsulate imaging material.
 40. A method according to claim 39,wherein said imaging material comprises coloring material.
 41. A methodaccording to claim 36, wherein said ambient conditions is reflective ofhumidity conditions around the photosensitive media in the cartridge.42. A method of controlling image development comprising: providing anambient condition sensor in a cartridge which holds photosensitive mediatherein, said ambient condition sensor sensing ambient conditions aroundphotosensitive media in the cartridge, said ambient condition sensorcomprising at least a cover layer and a conductive layer, wherein a rateof response to ambient conditions of at least said cover layer matches arate of response to ambient conditions of the photosensitive media inthe media cartridge; inserting the cartridge to an insertion position ina printer which permits a passage of photosensitive media from thecartridge to the printer; sensing ambient conditions around thephotosensitive media by way of the ambient conditions sensor; andcontrolling a development of images on the photosensitive media based onthe sensed ambient conditions.
 43. A method according to claim 42,wherein said cover layer is a humidity responsive layer and saidconductive layer comprises conductive interdigited fingers and first andsecond electrical contacts.
 44. A method according to claim 42, furthercomprising: adding an image composition layer to said conductive layerhaving said cover layer thereon, such that imaging properties of saidambient condition sensor matches imaging properties of thephotosensitive media in the cartridge.
 45. A method according to claim44, wherein said image composition layer comprises microcapsules whichencapsulate imaging material.
 46. A method according to claim 45,wherein said imaging material comprises coloring material.
 47. A methodaccording to claim 42, wherein said ambient conditions is reflective ofhumidity conditions around the photosensitive media in the cartridge.48. An ambient condition sensor for a photosensitive material imagingarrangement, the ambient condition sensor comprising: a cover layer anda conductive layer, wherein a rate of response to ambient conditions ofsaid cover layer matches a rate of response to ambient conditions of aphotosensitive material to be developed.
 49. A sensor according to claim48, wherein said cover layer is a humidity responsive layer and saidconductive layer comprises conductive interdigited fingers and first andsecond electrical contacts.
 50. A sensor according to claim 48, furthercomprising: an image composition layer, such that imaging properties ofsaid ambient condition sensor matches imaging properties of thephotosensitive material to be developed.
 51. A sensor according to claim50, wherein said image composition layer comprises microcapsules whichencapsulate imaging material.
 52. A sensor according to claim 51,wherein said imaging material comprises coloring material.
 53. A sensoraccording to claim 48, wherein said ambient conditions is reflective ofhumidity conditions around the photosensitive media.